Page:Hardwicke's Science-Gossip - Volume 1.pdf/34

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18
SCIENCE-GOSSIP.
[Jan. 1, 1865.

roots penetrate to double the depth of ordinary ploughing; we raise up the turnip on drills to help it, and we expect the pulse and grass crop to perforate and deepen the soil to help us. But there is not a cultivated plant which does not naturally send down its roots beyond 9 inches. The cereals on which our agriculture mainly depends are, indeed, endowed with the power of forcing their roots deep and far into the solid earth in search of food, and as the investigation of drainage obstructions has lately shown, it is impossible by any process short of actual tracing, to fix the distance to which the roots of trees and hedge plants will penetrate; so is it found that wheat and our other cultivated grasses extend their roots much further into the soil than is at all generally supposed; Johnston, in his drainage lecture, says that deep-rooted plants, such as lucerne, often fail, even in moderately deep soils, because an excess of water, or the presence of some noxious ingredient which deep drains would remove, prevents their natural descent in search of food. "Even plants," he adds, "which, like wheat or clover, do not usually send down their roots so far, will yet, where the subsoil is sound and dry, extend their fibres for three or more feet in depth, in quest of more abundant nourishment." But, I repeat, it is not thoroughly understood how deeply the roots even of wheat and clover descend. The Earl of Macclesfield, in a letter to the Society of Arts, mentions that a few years ago, Mr. Badcock, a shrewd, sensible, observing, and very considerable farmer, at Pyrton, Oxon, having occasion to dig the foundation of a building on a field under wheat, was much surprised by observing the small fibres of the roots of the wheat much deeper in the earth than he had any idea of. Endeavouring to trace how deep they really went, he had the ground opened close to some plants, dug perpendicularly down to the depth of 6 feet, and having fixed a narrow board close against it, proceeded in the same manner on another side of the plant, and so on till he had secured the earth to that depth between four boards firmly lashed together. He then had it placed upon an inclined plane, and carefully removing the boards, with great caution and perseverance washed away all the earth adhering to the root and its very small fibres, and was much surprised at their extent. He repeated the trials on several other wheat plants, and traced their depth to within 5 or 6 feet. The late Mr. Fane, M.P. for Oxfordshire, had one of these plants, now presented by Lord Macclesfield to the Society of Arts, secured in a close glass tube. My friend Dr. Atkin and myself have traced the roots of wheat in Berwickshire, to 5 or 6 feet of perpendicular depth in garden soil.—Wallace Fyfe, Lecture at Royal Agricultural College.

China Grass.—The French Minister of Agriculture and Commerce has ordered over a quantity of China-grass seed (Bœhmeria nivea) from its native country, in order to distribute it to all agriculturists who may apply for it. If unsuccessful in the efforts to acclimatise it in France, it will probably succeed in Algeria. It may not be generally known that this plant (which is a large nettle) yields a beautifully soft, strong, and glossy fibre, applicable for the manufacture of linen fabrics.

Abnormal Development in the Pimpernel.—Dr. Marchand, in a recent contribution to botanical science on vegetable monstrosities, gives a curious account of abnormal forms in the common pimpernel (Anagallis arvensis), which is thus summarized by M. J. B. in the Gardener's Chronicle:

"We will take that instance first in which the parts of the flower departed least from the more normal condition, and then the others in their proper order. In all the parts there was a greater or less tendency to assume a green tint; in some they were entirely green, in others the brighter colours were confined to the more recently developed parts.

"1. In the first case, then, the sepals and petals were in their normal position, though rather more dilated than usual; the anthers were fertile, the principal change existing in the ovary, the upper part of which was wanting, so that the ovules were exposed seated on the central placenta.

"2. In the next step the calyx, more developed than usual, was separated from the corolla by a long peduncle; and the ovary, which was ovate, contained instead of a placenta a sort of plumule or young shoot.

"3. In this case the corolla and calyx were distant from each other; there was no trace of stamens, but the axis was continued from the centre of the corolla, and ended in a leaf-bud.

"4. The calyx and corolla nearly as before, but instead of stamens a whorl of little leaves was developed, in the centre of which the axis was continued, bearing at its tip two whorls of leaflets alternately three and three.

"5. In this case two out of the five stamens were normal, the other three changed into leaves, showing clearly the origin of the leaflets in the last case, which took the place of the stamens.

"6. The ovary varied in different flowers. In some the placenta was crowned with ovules; in others the ovules were replaced by a single whorl of leaflets; in others there was every shade of change from ordinary ovules to perfect leaflets; while in others, again, every ovule was converted into a leaf with a long petiole.

"7. We now come to another form in which shoots were developed in the axils of the sepals, or on the face of the petals between the point of their insertion and that of the stamens, and, what is most curious, in the interior of the ovaries round the foot of the placenta.